Emergency: California’s Oroville Dam Spillway Near Failure, Evacuations Ordered

Breitbart ^ | Feb 12, 2017 | Joel B. Pollak1

[janetjanet998]

The California Department of Water Resources issued a sudden evacuation order shortly before 5 p.m. Sunday for residents near the Oroville Dam in northern California, warning that the dam’s emergency spillway would fail in the next 60 minutes.

The Oroville Dam is the highest in the nation.

[Jim W N]

I’d say that bulk of unconcerned CA population doesn’t include residents of Oroville and others below this increasingly dangerous dam.

[Jim W N]

You cannot get away with fooling the laws of nature, even if politics & PR desires such

FYI, same with the laws of economics. Same deliberate government blindness, different subject.

[Jim W N]

ER333,

1)Would you say the Oroville Dam is firmly in the intermediate stage of failure?

2) Other than that, do you see any critical repairs that are still being implemented inadequately?

[EarthResearcher333]

The Army Corps can release more water out of the lake but they want to minimize the flooding. So they are doing a balancing act in using the lake as a collection buffer to prevent flooding surges.

Their tradeoff of doing this is that the height of the lake will rise to levels that will test the integrity of the dike system by an increased head pressure. Thus the need to constantly monitor for any piping or boils that may form from weak areas succumbing to internal water penetration/flow.

Daily inspections would allow them a quicker response time to identify a developing boil and swiftly implement a localized mitigation to shore up that location.

What is important is the Factor of Safety of the dike. If they push it beyond the actual Factor of Safety, i.e. IF it is less than what they think, they could have to deal with an outbreak of weak spots in the dike.

At that point, they would have no choice but to greatly increase the outflows. This would cause downstream flooding, especially when more rain is expected in the outflow regions that will add some to the ultimate flood height levels.

So the key to watch for on the "unexpected" is if a slew of "weak spots" outpace their mitigation response ability. Then they risk a breach potential where the large mass of the lake could cut through, swiftly erode a section of dike (full dike failure), and then inundate the surrounding area of the breach.

Since the U.S. Army Corps are controlling the outflows, and they know the lake rise potential with the incoming anticipated precipitation, then this infers that the Corps has "options"*. For now, they are doing what they can in mitigating flood damage.... (*just as long as nobody is crossing their fingers)..

[EarthResearcher333]

The best way to answer the first question is addressing the responsibility to make the dam & spillway structures as safe as reasonably possible. This is known as "As Low As Reasonably Practical" or ALARP. This is how Risk Management of systems is measured by.

The degree of ALARP is proportional to the risk to life & property. Oroville is in the highest risk hazard category in this regard. Thus, it is required to have the highest degree of ALARP in KNOWN conditions of the Dam & Spillway.

As it was well illustrated in the recent "NBC Investigates" TV news show airing, the retired DWR engineers and other reviewing engineers revealed inside information that DWR is not operating the Dam & Spillway to these required stringent safety conditions.

So, by these modern standards, which are also applied to nuclear power plants, nuclear powered submarines, FAA aircraft maintenance, etc - DWR has failed. DWR cannot assure the public that the risk is as low as reasonably practical. In essence, with the UNKNOWNS, just like they found out in the two spillway failures, there are uncertainties that remain that are not 100% tested and KNOWN - such as the internal phreatic water condition inside the dam.

The DWR insiders also testified in interviews about the 16+ foot crack in the headworks, and about the cracking & failing anchor tendons in the headworks. DWR admitted that the loss of control of a gate or gates means the risk of loss of control of flows (potential failure mode). Evidence tends to support that there is a real failure mode in a "jamming" risk from a problem in Gate 8 (and possibly Gate 7 as a trunnion pin anchorage is shared).

Just like NBC noted, DWR kicked the can down the road on important issues that were known years ago. Now they face not having the time to respond to prevent a failure (it could take a year or longer to fully replace the headworks).

If DWR miscalculated their choice of using seepage at the toe drain as an indicator to replace a KNOWN method of determining the dangerous internal swelling from a pressurized phreatic condition in the Zone 3 embankment (using piezometers), AND the highly fractured left abutment is drawing water away from the toe drain system (including "clogging" effects), then the dam risks exactly what NBC showed in their graphic - a sudden onset in days of a catastrophic collapse of the dam (just like Teton in 1976).

As for the second question: If the headworks or the dam fails, it doesn't matter what has been fixed on the new spillway. Keep in mind that they placed ~3,000 rock anchor bolts in the 730 ft of the leftover original Upper Spillway. This is an extreme level of anchorage to slabs that DWR purported was "safe" and is "doing fine" before the BOC told them it wasn't (actions speak louder than any non-spoken item or redacted item in BOC memos).

The only item on the new spillway that is structurally "off" (i.e. mismatch) is the high ratio of anchor bolts & plates in the sidewall slabs compared to the structural intersection strength of the vertical sidewall (weaker). If you calculate the combined strength they believed necessary for this higher density ratio of anchor bolts & plates in the sidewall slab, it doesn't match the structural design capacity of the intersecting rebar at the base of the vertical sidewall.

However, the new spillway is so much better in design and structural improvements over the original that this spillway fully meets modern standards with a good Factor of Safety well above and beyond.

[Jim W N]

the dam risks exactly what NBC showed in their graphic - a sudden onset in days of a catastrophic collapse of the dam (just like Teton in 1976)

That sounds an awful like we're at the brink of final stage failure needing only a final shove of enough water. I suppose technically, we're not into the final stage until the actual physical failure has begun - ie. the "domino affect" has begun that can't be stopped.

If I were living in Oroville and were following your and the NBC analysis here, I would have figured out a way to move even knowing that selling my house might be impossible - I'd be potentially saving our lives.

I'd move and rent or something until either the dam broke and hopefully insurance would cover the house or somehow this thing were fixed over the next year(s) in time to move back. I think I'd have ground for a suit to cover the expenses.

I would think a lot of people would be doing this right now.

[EarthResearcher333]

Glimpse of Longitudinal Drain & slow Grade angle separation (Upper Spillway) - Lower Spillway Junction to RCC section being prepped for const concrete pour

First photo shows Rebar metal support stands providing an angled grade to the longitudinal (parallel to the spillway) drain pipe. From a water flow perspective, this drain pipe is angled downward (downslope) even though the image gives the impression of an upward angle. The separation of the angle to the lower fill concrete base, with respect to the drain pipe, is from the sharper downhill grade of the spillway.

This longitudinal drain pipe likely connects to multiple "across the spillway" drain channels just as shown where the construction worker is filling in a drain channel with filter gravel. Inside this filter gravel is a large pipe that is perforated to allow collection of any seepage water (from any seepage above or below the pipe).

The second photo is the prep work underway at the junction to the lower spillway construction concrete section to the RCC start section. Long anchor bolts and plates have been emplaced at an angle to transfer anchorage into a wider area of the thick RCC section (right). Another row of anchor bolts and plates are lined up in the construction concrete (left). Thus, both sections will share in the anchorage in the soon-to-be poured construction concrete to fill this gap. The mini-excavator has an attachment to pulsate and hammer a steel pointed tip to form the desired gap shape (widen the base). An additional photo shows a large group of workers hand removing the chunks and cleaning this seam area from leftover debris.

We'll see later how they intend on handling the expansion/contraction of the additional layer of chemically hardened RCC layer and the construction concrete layer, and any re-inforcement steel that will straddle this junction seam area, to match up with the finished surface grade of the spillway.

Photo 1 - Rebar metal support stands providing an angled grade to the longitudinal (parallel to the spillway) drain pipe. From a water flow perspective, this drain pipe is angled downward (downslope) even though the image gives the impression of an upward angle.

Photo 2 - Prep work underway at the junction to the lower spillway construction concrete section to the RCC start section. Long anchor bolts and plates on both concrete sides to facilitate securing this concrete pour for the junction. Mini-excavator "widening" the lower base area of the "V"

[mad_as_he$$]

My family had some business interests in Oroville through a cousin. We convinced them to sell out - at a loss and relocate to “higher ground” early on in this event. I sleep better now knowing that they are safe from this dam and the DWRs appalling "management".

[Jim W N]

My family had some business interests in Oroville through a cousin. We convinced them to sell out - at a loss and relocate to “higher ground” early on in this event. I sleep better now knowing that they are safe from this dam and the DWRs appalling "management".

I'm glad to hear that.

I have to believe that the only reason there isn't a mass exodus from Oroville and environs below the dam is the residents simply aren't aware of the heightened level of risk and danger that may very well be at or close to the brink of Stage 3 Failure and collapse.

[EarthResearcher333]

RCC rising - Oct 4

Spillway slope fill area noted via arrows. The Roller Compacted Concrete rise in elevation should accelerate in the coming days. The tapered outer RCC is deceptive in its additional bulk to the total volume required just to meet the angled slope noted by the arrows.

RCC is progressing quicker in the vertical lift placement. Good weather and no plant breakdowns would keep the schedule secure for the end of the month "meet-up" date to the new upper structural concrete section.

[Repeal The 17th]

Still a lot of concrete left to be placed,
plus the erection of the temporary sidewalls.

[KC Burke]

I still say that filling in Moonbeam Canyon with those Bullet Trains of Jerry’s would have been faster than all this Roller Compacted Concrete substrate.

[steve86]

And I’m worried about getting my concrete driveway replaced by the end of October.

[EarthResearcher333]

Opinion verses Engineering - to those downplaying the NBC Investigation

Ultimately it is the public that faces the risk of good or bad engineering & maintenance operations from a High Risk Structure such as Oroville Dam.

For those, in the greater social media world, that have inferred or said that that the NBC investigative report was "classic hysteria to raise fear/anxiety for ratings", there are in-depth engineering facts and history which have not been addressed. There is a responsibility for "sources" to understand the field of expertise they are reporting on and recognize that "one side's" presentation of "history" has been fraught with proven faulty analysis. To continue to fully accept "one side's" presentation of the safety of the dam, without the expertise to discern "one side" verses the "other", then there's a potential for risking efforts to insure the safety of the dam, and thus the safety of the public.

There is more that was not revealed in the NBC investigates report. How is this known? There are sources that do know and have confided.

This is the reason why former DWR sources chose to be protected in their identity for the interviews. Follow the evidence. NBC revealed the tip of the berg. But there must be a specially applied field of expertise to recognize the full truth & to discern from "one side's" perspective.

Below is information provided from a "source" - I know the "source". This information is relevant to the above.

=========

A history of inadequate engineering analysis by DWR - Two Spectacular Failures

A history of inadequate engineering analysis by DWR has revealed to the public the degree of these consequences from two spectacular failures at Oroville Dam. Because of these deeply flawed analyses, it resulted in the immediate evacuation of 188,000+ people, with less than an hour's warning to a "failure", with a possible 30 foot high wall of water racing down into the nearby towns. Panic spread as the escape roads were clogged from vehicles with residents fearing for their lives.

This first engineering analysis failure stemmed from DWR's claim that the Emergency Spillway was on "solid bedrock" and there was no risk. Yet their analyses were severely flawed, and proven incorrect, as the Emergency Spillway failed at only 3% of its rated capacity. The cause was found from an improper analysis of the erosion characteristics of "highly weathered fractured rock" - called rotten rock, not solid bedrock. The Emergency Spillway hillside had widespread and deep layer of highly erodible "rotten rock", not "solid bedrock" as they had claimed.

The second engineering analysis failure led to the blowout destruction of the massive concrete Main Spillway. DWR claimed the Main Concrete Spillway was constructed and anchored upon "Extremely Competent Rock". It was not. Their own historical Geological and Construction engineering reports revealed the Main Spillway was constructed upon large and deep clay seams, not solid bedrock. The Main Spillway experienced a "blowout failure" with extreme hydraulic pressures developing underneath the concrete slabs. The failed Main Spillway had to continue to be operated with high water flows to keep the failing Emergency Spillway hillside from triggering a "toppling" of the tall concrete Emergency Spillway Weirs. The Main Spillway Failed at only 18% of its rated capacity.

New inadequate engineering analysis - Leading to a Sudden Dam Failure? - a Third Spectacular Failure?

DWR has chosen again to selectively present information dismissing a potential dangerous leak in the dam to be "only from rainfall". Again, their analysis is deficient regarding a comprehensive investigation to accurately establish that there is no risk from a dangerous leak within the dam. DWR does admit there is a process of "suffusion" occurring on the backside of the dam in large "Erosion Channels". Yet they fail to test or measure how deep this suffusion of fine materials goes into the embankment. Without this knowledge of the extent of the deep migration of sands and fine materials in the mix of the boulders, rocks, and cobbles, the stability of the dam may be structurally compromised. There are many more other engineering evidence examples that have been dismissed in DWR's analysis - that was given to the public in their recent report on the Dam.

A comprehensive rebuttal 129 page report was created by concerned engineers and scientists regarding the dangerous oversight DWR's recent Dam report analysis. I have studied this extensive report and I fully agree with the findings. This full report has not been released to the public, however I have permission to share a "Summary section" of this report below. There are other important references, articles, and interviews below that further detail this risk to Oroville Dam.

Will the Public get any Warning to a Sudden 770 ft tall Dam Failure?

The lack of any warning to the hundreds of thousands of residents from a 770 foot tall Dam Breach Failure is of the greatest concern. A faulty engineering analysis will lead engineers - and the public - to believe that there is no risk of a sudden dam failure. DWR is under extreme public pressure from the two prior Spillway Failures. Currently, DWR is facing a class action lawsuit with claims of nearly $1.6 Billion Dollars from the consequences of these two failures in flood releases, evacuations, property value losses, lost business revenue, and farmland destruction. Given this history, and the history of DWR's exhibited priority of "Public Relations Image" concerns, engineers would be extremely hesitant in issuing a warning if an outside embankment surface leak were to suddenly develop.

It was by God's Providence that Law Enforcement (Sheriff) discovered the imminent Emergency Spillway failure threat. The Sheriff called an emergency meeting with DWR officials and swiftly drove the decision to notify the public to evacuate. It was by a sheer accident that the Sheriff discovered the Emergency Spillway Failure danger as he overheard a comment from a DWR engineer. The Sheriff was not notified by DWR of the immediate failure danger as he was originally heading out of DWR's offices.

However, a Dam Breach Failure would escalate quickly to where there would be little to no time to investigate. Any delays of indecision by DWR engineers, directors, and public relations - since they fully believe that there shouldn't be a leak through the dam - could cost tens of thousands of lives or more. The Breach Failure and collapse of the 1976 Teton Dam in Idaho and the 1928 St. Francis Dam in California starkly demonstrate this where there was little time left to investigate before their sudden collapse.

With God's Providence again, it may be through social media, private citizens, a conscientious engineer, and possibly a Sheriff being in the right place at the right time, in discovering and revealing the early warning leakage, which may be the only warning the citizens may receive.

===

[1] === "NBC investigates" news story link

http://www.nbcbayarea.com/investigations/Records-Raise-Safety-Questions-Surrounding-Oroville-Dam-448318083.html

Scott Cahill: Collapse Risk At The Oroville Dam Is Still Unacceptably High

https://www.youtube.com/watch?v=GHI_CcHXr6E Oroville Mercury Register, Risa Johnson, Sept 6, 2017

http://www.orovillemr.com/article/NB/20170906/NEWS/170909834 “Oroville Dam could end up in the history archives as the greatest natural disaster in California history, if not in the entire United States, if it is later found to be from a destabilizing internal leakage that led to a sudden breach of the dam,” they wrote.

------- OROVILLE DAM FAILURE? -- September 5, 2017

(Special Permission to release - "Summary section" of New Sept 5, 2017 report. 129 page Report that contains extensive data & analyses from concerned scientists & engineers)

REPEAT OF ST FRANCIS DAM AND TETON DAM FAILURES? Appendix A reveals that DWR* faces crucial uncertainties, conflicts in analyses, and an extensive lack of consideration of critical relevant factors, in the current seepage report (presented as "rainfall only") regarding an accurate determination to the source to the Dam Green Wet Area. Appendix A details the history, the extent, and relevance of these numerous critical issues that should have been fully analyzed and thoroughly investigated regarding the Green Wet Spot Seepage Anomaly. This compilation includes DWR's consideration, but then dismissal, of an Oroville Dam Failure condition leading to a potential major Dam seepage related failure (item 31).

The described Oroville Dam failure sequence is near identical to the abutment seepage and the subsequent swift and catastrophic breach failure of Idaho's Teton Dam in 1976. Yet, between DSOD** and DWR there have described and noted four different versions of the "source" of the seepage, each of which conflicts in evidence between the versions with respect to each other. With "versions" ranging from DWR noting to FERC in a 2014 Part 12D detailed analysis that the "seepage source" is from a "plurality of an existence of natural springs", to a singular "a natural spring" in an April 2017 town hall meeting, then to DWR changing to a narrative of "rainfall only" in their newly released report. Conspicuously missing in the new DWR report are DSOD inspection reports detailing strong evidence of a "through the dam leakage" path, in defining the "reservoir" as the seepage source (2014 and 2015 inspections). Most notably, the DSOD July 2015 inspection report found wet seepage on the face of the dam even in a severe heat and an on-going drought which included photographs of brown grass. Thus any narrative of a "nothing to worry about" emphasis in placing the seepage source as "rainfall only", with so many unanswered questions, may result in a dangerous complacency.

The Left Abutment has proven to have numerous cracks, in the metavolcanic rock, that surprised DWR in its stability behavior by the large 100,000 cubic yard rockslide during construction; even after the rock excavation was "thought to be" completed. DWR blamed the destabilization from heavy water penetration into "cracks" in the rock that triggered the massive landslide. This same nature of a geological surprise, in unexpected geological abutment conditions, was a primary root cause to the failure of St Francis Dam in 1928. Yet, with no working piezometers in the dam, DWR is heavily placing the measured safety of the dam using simple peripheral seepage points as "indicators" from the toe drain, gallery tunnels, and core block seepage. Thus, any "lost" or "unseen" water penetration, that escapes these "indicators", could go unnoticed until the potential event of a sudden breach failure occurs.

Indeed, a DSOD inspection report notes a volume of water penetration, increasing every year, through deep rock cracks in the Left Dam Abutment into the Hyatt Power plant. This clearly demonstrates the ability for water to migrate deep into the Left Abutment rock through cracks. This level of high "transmissivity" in the Left Abutment Rock has the ability to divert internal "unseen leakages" away from the toe drain seepage weir. With DWR critically depending only on these "indicators", without any internal piezometers or sensors providing "definitive proof", DWR is making a High Risk choice that has a "catastrophic High Risk potential" that was well described in their Part 12D Dam Failure exercise in 2014. This was dismissed by DWR as their version was from a different core leakage mechanism (DWR had not considered Left Abutment slope induced failure mode of "Differential Settlement" in the Part 12D analysis exercise). Until DWR answers all of the crucial relevant factors, with a thorough investigation and using "in the dam" piezometer instrumentation giving solid "proof" data, Oroville Dam could end up in the history archives as the greatest natural disaster in California History - if not in the entire United States - if it is later found to be from a destabilizing internal leakage that led to a sudden breach of the Dam.

*DWR - California Department of Water Resources

**DSOD - California Division of Safety of Dams

[EarthResearcher333]

Yes, the sidewalls are significant. Thus the seemingly deceptive fill to the end.

The dark section of the RCC on the spillway shows the progress rate at or near the maximum "football field" sized area. The volume of fill in the recent days reveals its significance.

This photo was to show the tapering effects of the effort, but they have a ways to go. That is why the mention of the weather & the RCC plant.

[Repeal The 17th]

They have to place the RCC in 2 foot ‘lifts’, is that right?

[EarthResearcher333]

LOL

[EarthResearcher333]

Photographs show a "lift" height closer to 1 foot on the sloped spillway grade (KJ_oroville_0710_09_19_17.jpg). If the Horizontal "lift" corresponds, then the lift value would be closer to a 1 foot height average. Yet in the distance in this photo, it shows a lift height that is higher than 1 foot near the thick sidewalls.

Kiewit may be doing a variable application based on the equipment compression (roller compactor verses the excavator "shaping" flat plate for the spillway slope).

Other info: They were placing RCC, compacting it, and raising the large "football field" size area about 5 feet per day. This was close to where they placed a record amount of 3,143 cubic yards of RCC in one 12 hour shift.

Currently they are close to 70 percent of the estimated 350,000 cubic yards of RCC that makes up the middle section. Kiewit has stated that they have placed 230,000 cubic yards of RCC to date and have 85 vertical feet to go (as of Oct 4).

[KC Burke]

Good overall at 4334 — thanks. I read through it fairly quickly as I still need to get my coffee pot started, but it seems the trunion/gate problems were not even added to the issues yet along with the related adjacent structure crack progression.

We will see this huge expenditure on the spillway and emergency spillway successfully completed and still have a very flawed dam.

[EarthResearcher333]

Crane Exit Path - Root Ball Removed - Hillside work - Curved form puzzle

The mid-spillway crane has exited stage right. Just in time for the sidewall section "joining". There is a small hillside "jog" that likely was filled in with support cribbing & wood to facilitate an even weight distribution. You wouldn't want to have a focused weight on the back tracks so as to protect the finishing concrete layer.

Another interesting question arises on the curved sidewall form that is laying in the spillway next to the far sidewall. This may have been an unintentional result from excessive adhesion in removing the sidewall from the concrete pour.

How? The inner wood of the sidewall forms are coated with a material that is intended to facilitate a non-bonding interface to the newly poured concrete. If this interface coating isn't "just right" the pull forces to remove the form may result in what is currently the "bent condition" of this form. The form has a set of seven steel dual "ribs" that are designed to "stiffen" the form. The bent nature of the form reveals the strong forces to cause this curvature of the array of steel ribbings.

The other possibility is that these forms are intentionally slightly curved in construction to facilitate a positive contact force with the internal spacer blocks. Anchoring the form in the concrete with temporary bolts at the bottom and then the steel supports maintain the upper form positive contact force.

When comparing the Sep 18, 2017 post 4262 photo of the crane in the spillway, there are forms stacked that are straight and true that are adjacent to a "curved" form. Thus, contradicting the supposition of a pre-curved construction approach.

Optimal construction requires the "reuse" of these forms. Perhaps they have a way of rehabilitating or readjusting a form back to its reusable state - without a significant amount of work.

Perhaps a time lapse series of the construction would give clues to this puzzle.

How will they Get the Crane Out? (Post# 4262)

Crane exit path revealed. Wood support materials likely used for small hillside climb & to distribute the weight over the leveling concrete. Near picture view reveals root ball has been removed plus rock materials. The original tree with the "cut" remains in this photo.